The PCMCIA recently introduced the PCMCIA ExpressCard standard as a successor technology to the venerable PCMCIA PC Card and PC Cardbus standards. PCMCIA ExpressCard slots are available today on a wide range of host systems. More and more peripheral devices based on PCMCIA ExpressCard are appearing everyday. Based on and supporting both the very fast PCI Express (PCIe) and ubiquitous USB 2.0 standards, ExpressCard is smaller, faster, and much simpler to deploy than the previous expansion technologies like PCMCIA PC Cards.

ExpressCard's flexibility and high speeds provide breakthrough applications including full throughput eSATA host adapters, UDMA 4/PIO Mode 6 supporting CompactFlash adapters, and FireWire 800 host adapters. All new is the availability of ExpressCard slots deployed on desktop machines for PCIe 1X applications, alleviating the problem of opening a computer's case when installing new peripheral devices.

Host Adapters Providing ExpressCard Read/Writer Capability

PCIe to PCMCIA ExpressCard readers allow PCIe based desktop computers to utilize ExpressCard applications. Such readers are completely transparent to any card inserted, accepting either ExpressCard 34 or 54 cards. ExpressCard drives themselves require no drivers, but the cards being used with them might. PCIe to PCMCIA ExpressCard reader's PCIe 1X configuration realizes full 250MB/s (megabytes) throughput with PCIe based ExpressCards, while USB 2.0 ExpressCards operate at a 480Mb/s (megabits) speed. Excellent for sharing devices between modern laptops and desktops, PCIe to PCMCIA ExpressCard drives are a smart addition for desktop machines. Online stores offer PCIe to ExpressCard readers that work with both ExpressCard 34 and ExpressCard 54 Cards.

ExpressCard is the PCMCIA's newest removable, portable, expansion technology to replace 16-bit PC Card and 32-bit PC Cardbus card devices. As a technology based on the latest bus standards, ExpressCard holds several advantages over PCMCIA PC Card some of which are explained below.

ExpressCard offers two all new interconnect technologies

ExpressCard utilizes two interconnect technologies, the most important of which is PCI Express (PCIe). ExpressCard devices utilizing PCIe 1X technology are capable of 2.5Gb/s per direction. An ExpressCard operating in full duplex mode has an approximate throughput of 250MB/s x 2, or 500MB/s of throughput. This is about four times the effective speed of 32-bit PC Cardbus. Alternatively, ExpressCards utilizing USB 2.0 for less complex and lower speed applications, have a maximum throughput of 480mb/s.

ExpressCard's bandwidth provides much higher performance

PCIe 1X technology based ExpressCards are capable of 2.5Gb/s per direction, allowing for realization of applications, like host adapters, which underperform or are impossible with PC Cardbus. Examples of bottlenecked Cardbus host adapters, that don't tax ExpressCard are Gigabit Ethernet (GbE) and FireWire 800 (IEEE 1394.b). Furthermore, ExpressCard will be able to handle the newest SATAe and other high end busses with relative ease.

ExpressCard replaces a parallel bus with a high speed serial bus

ExpressCard follows the trend of SATA and PCI Express of a transition from parallel to serial buses. ExpressCard utilizes a 26-pin beam on blade serial connection, rather than the 68-pin parallel connection used for PC Card. ExpressCard's utilization of PCIe and USB 2.0 serial connections built in host systems reduces complexity. It also eliminates signal timing problems associated with parallel buses.

ExpressCard is inexpensive and easier to implement than PC Card

Since ExpressCard harnesses busses already existing on the newest host systems, it doesn't need separate ASIC bridge chips for integration. Differing from PC Card and PC Cardbus which required a controller chip to bridge underlying system bus to the card slot, ExpressCard devices essentially plug into either the system's PCIe or USB 2.0 bus, based on the type of ExpressCard employed. Savings in both cost and complexity are a hallmark of ExpressCard.

ExpressCard offers superior power management and saving

ExpressCards operate at 1.5 and 3.3V baselines, which are lower voltages than PC Card. Systems deploying ExpressCard technology can take full advantage low power utilization and allow for longer batter life in portable applications.

Yes, the innovative DuelAdapter ExpressCard 34 to PCMCIA PC Card and CardBus Read-Writer allows any system with an PCMCIA ExpressCard slot to use both legacy 16-bit PC Cards and 32-bit PC Cardbus Cards. The host computer can have a native ExpressCard 34 or ExpressCard 54 slot, or have a PCIe to ExpressCard adapter and work with the DuelAdapter. As long as the PCMCIA PC Card is supported by the underlying operating system, it will work when used in conjunction with the DuelAdapter.

For USB 2.0 based ExpressCards, yes. Several devices act as USB 2.0 hubs, passing USB 2.0 signals from an ExpressCard through to a PCMCIA PC Card slot. These PCMCIA PC Card to USB 2.0-Mode ExpressCard adapters come in both 32-bit and 16-bit PCMCIA PC Card types. PCMCIA to USB 2.0 based ExpressCard adapters do not work with any PCIe based ExpressCard. Technically, there adapters break the PCMCIA specification, since a given host slot is supposed to support both the PCIe and USB 2.0 portions of the ExpressCard standard.

ExpressCard slots, like ExpressCards, come in two varieties; those for both ExpressCard 54 and 34 cards, and slots for ExpressCard 34 cards only. Regardless of their physical dimensions ExpressCard slots are required to provide both PCIe and USB 2.0 functionality. ExpressCard 54 slots, as seen in figures A and B on the right, accept both 54 and 34 cards. What PCMCIA terms as a "novel guidance device," physically guide an ExpressCard 34 device to the connector part of the slot, as seen in the lower left corner of figures A and B. With the connection portion of ExpressCards for both types being an identical 34mm, this scheme enables an elegant way to utilize either type of card. Conversely, ExpressCard 34 slots only accept ExpressCard 34 cards as seen in figure C. This last fact is important when shopping for ExpressCards, if a device only accepts ExpressCard 34 slot, then only look for ExpressCard 34 devices. The PCMCIA's literature states systems deploying multiple ExpressCard slots should lay them out on a horizontal plane adjacently rather than a "stacked slot" convention employed for PC Card slots.

ExpressCards are available in two form factors: ExpressCard 34 and ExpressCard 54. These form factors share identical dimensions except for width, which is where the form factor names are derived. ExpressCard length is 75mm and their depth (or thickness) is 5.0mm. 5.0mm is the same depth as PC Card Type II. While the shapes and widths of ExpressCard form factors differ, the portion of the card connecting to the card slot are identical at 34mm. ExpressCard 34 cards are rectangular in shape and 34mm wide. ExpressCard 54 Cards at their widest point are 54mm wide, but 34mm wide at the connection point, creating a "Fat-L" shape. Both form factors are allowed additional volume extending outside of what is considered the flush portion of an inserted card. Referred to as the extended portion of the card, ExpressCards with such configurations are called extended cards. Extended portions may exceed a card's dimension on any axis, with obvious practical limitations. For an example of an ExpressCard 34 featuring an extended portion on two axis (depth and width) see: ExpressCard 34 to CompactFlash Memory Card Adapter. See ExpressCard Physical Slotting for a Image of how ExpressCard modules are deployed in the two types of ExpressCard slots.

PCMCIA ExpressCard and PCMCIA PC Card Data Table

16-bit PC Card

32-bit PC Cardbus

ExpressCard (USB 2.0)

ExpressCard (PCIe 1X)

Voltages

3.3/5.0/12.0V

3.3/5.0V

1.5/3.3V

1.5/3.3V

Maximum Throughput

20 MB/sec.

132 MB/sec.

60 MB/sec.

250 MB/sec. per direction

PC Cards

ExpressCard 34

ExpressCard 54

Depth

Type I/II/II

3.3/5.0/10.3mm

5.0mm

5.0mm

Length

85.6mm

75mm

75mm

Width

54mm

34mm

54mm

ExpressCard Product Sources

Many online vendors offer a wide range of ExpressCard 34 and ExpressCard 54 products including Synchrotech.